Antifungal drug-resistance mechanisms in Candida biofilms

Abstract

Infections caused by the Candida species of human fungal pathogens are a significant medical problem because they can disseminate to nearly every organ of the body. In addition, there are only a few classes of antifungal drugs available to treat patients with invasive fungal infections. Candida infections that are associated with biofilms can withstand much higher concentrations of antifungal drugs compared with infections caused by planktonic cells, thus making biofilm infections particularly challenging to treat. Candida albicans is among the most prevalent fungal species of the human microbiota, asymptomatically colonizing several niches of the body, including the gastrointestinal tract, genitourinary tract, mouth, and skin. Immunocompromised health conditions, dysbiosis of the microbiota, or environmental changes, however, can lead to C. albicans overgrowth, causing infections that range from superficial mucosal infections to severe hematogenously disseminated infections. Here, we review the current knowledge of antifungal drug-resistance mechanisms occurring in Candida biofilms.

Keywords: C. albicans; Candida; antifungal drugs; biofilms; drug resistance.

Figure 1

Major drug-resistance and/or tolerance mechanisms in C. albicans biofilms. A schematic representation of the major C. albicans biofilm drug-resistance and/or tolerance mechanisms: the presence of the extracellular matrix, the upregulation of drug-efflux pumps, and the presence of persister cells.